Discodoris lilacina from sthn Queensland

Dear Gary,

Thanks for these photos. As your upper one shows, this is a hardy species whihch can sometimes be found even in upper tidal pools where they are in grave danger of cooking! In your lower photo we can see the papillae which cover the mantle and usually have a nipple-like tip. In the earlier message I mentioned Alder & Hancock's two species D. fragilis and D. concinna. Charles Eliot, who re-studied Alder & Hancock's specimens considered the two species could possibly be separated by the nature of the tubercles on the mantle. He described the tubercles of D. concinna as crowded and often with a raised tip as in your photo. Unfortunately the preserved material of D. fragilis was in pieces - probably due to the breaking up of the mantle on preservation - but he considered that the tubercles were not as crowded and different in appearance. I must say I have spent many hours trying to distinguish any differences in living specimens, but have been unable to find two 'tubercle types'. Until someone can show me some differences, I find the only practical solution is to use the oldest available name - Discodoris lilacina.

• Eliot, C. N. E. (1906) On the nudibranchs of Southern India and Ceylon, with special reference to the drawings by Kelaart and the collections belonging to Alder & Hancock preserved in the Hancock Museum at Newcastle-on-Tyne. Proceedings of the Zoological Society of London, [for 1906], 2, 636-691.

Best wishes,
Bill Rudman